Activated caspase-6 and caspase-6-cleaved fragments of huntingtin specifically colocalize in the nucleus

Warby, Simon C.; Doty, Crystal N.; Graham, Rona K.; Carroll, Jeffrey B.; Yang, Yuzhou; Singaraja, Roshni R.; Overall, Christopher M.; Hayden, Michael R.

doi:10.1093/hmg/ddn139

Cited by 114 publications

(103 citation statements)

References 65 publications

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“…34 This finding is also in agreement with genetic studies in drosophilla that established that DJ-1 is critical for mitochondrial function. 31 Cysteine 106 is functionally essential for DJ-1 function and is also subject to oxidation. An interesting observation of the present study is that stable expression of DJ-1 Nt in SH-SY5Y cell line alters the oxidation level of both native and cleaved DJ-1.…”

Section: Discussionmentioning

confidence: 99%

The caspase 6 derived N-terminal fragment of DJ-1 promotes apoptosis via increased ROS production

et al. 2012

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In pathological conditions, the amount of DJ-1 determines whether a cell can survive or engage a cell death program. This is exemplified in epithelial cancers, in which DJ-1 expression is increased, while autosomal recessive early onset Parkinson's disease mutations of DJ-1 generally lead to decreased stability and expression of the protein. We have shown previously that DJ-1 is cleaved by caspase-6 during induction of apoptosis. We demonstrate here that the N-terminal cleaved fragment of DJ-1 (DJ-1 Nt) is specifically expressed in the nucleus and promotes apoptosis in SH-SY5Y neuroblastoma cell lines. In addition, overexpression of DJ-1 Nt in different cell lines leads to a loss of clonogenic potential and sensitizes to staurosporin and 1-methyl-4-phenylpyridinium (MPP þ )-mediated caspase activation and apoptosis. Importantly, inhibition of endogenous DJ-1 expression with sh-RNA or DJ-1 deficiency mimics the effect of DJ-1 Nt on cell growth and apoptosis. Moreover, overexpression of DJ-1 Nt increases reactive oxygen species (ROS) production, and sensitizes to MPP þ -mediated apoptosis and DJ-1 oxidation. Finally, specific exclusion of DJ-1 Nt from the nucleus abrogates its pro-apoptotic effect. Taken together, our findings identify an original pathway by which generation of a nuclear fragment of DJ-1 through caspase 6-mediated cleavage induces ROS-dependent amplification of apoptosis.

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Section: Discussionmentioning

confidence: 99%

The caspase 6 derived N-terminal fragment of DJ-1 promotes apoptosis via increased ROS production

et al. 2012

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“…The drawbacks of these models are the loss of the natural genomic and protein context of the polyglutamine expansion, which could lead to altered regulation and a loss of potential disease-modifying post-translational modifications and protein interactions. Additionally, it has been shown that mHTT fragments generated by intracellular cleavage have a different subcellular localisation than truncated mHTT (Warby et al, 2008). It is therefore possible that the process of mHTT cleavage is in itself relevant to the pathogenesis of HD.…”

Section: Huntingtin Fragment Mouse Modelsmentioning

confidence: 99%

Mouse models of Huntington disease: variations on a theme

Ehrnhoefer

Butland

Pouladi

et al. 2009

Disease Models &Amp; Mechanisms

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An accepted prerequisite for clinical trials of a compound in humans is the successful alleviation of the disease in animal models. For some diseases, however, successful translation of drug effects from mouse models to the bedside has been limited. One question is whether the current models accurately reproduce the human disease. Here, we examine the mouse models that are available for therapeutic testing in Huntington disease (HD), a late-onset neurodegenerative disorder for which there is no effective treatment. The current mouse models show different degrees of similarity to the human condition. Significant phenotypic differences are seen in mouse models that express either truncated or full-length human, or full-length mouse, mutant huntingtin (mHTT). These differences in phenotypic expression may be attributable to the influences of protein context, mouse strain and a difference in regulatory sequences between the mouse Htt and human HTT genes.

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“…47 This allows easy detection of the mutant HTT 586 fragment without any other cleavage events occurring. We co-transfected 1212 128Q 4C HTT with WT CASP6 or mutant CASP6 C264/277S and found a significant~12% increase in cleavage of mutant HTT and generation of the 586 HTT fragment by palmitoylationdeficient CASP6 compared with WT ( Figure 3e).…”

Section: Resultsmentioning

confidence: 99%

“…The N-terminal 1212 amino acids of HTT with 128Q and the 4C mutations (D513A, D530A D552A, and D589A) were transiently transfected and overexpressed together with WT CASP6 or mutant CASP6 C264/277S in COS7 cells for 24 h. 47 Cell pellets from COS7 cells or Q111 and Q7 cells were lysed with SDP+ lysis buffer 65 and diluted in SDP+ lysis buffer to a final protein concentration of 2 μg/μl. 66,67 The detection of the 586 HTT fragment was performed using a combination of the monoclonal BKP1 antibody raised against the HTT N-terminus and an in-house 586 neo-epitope antibody raised against the C-terminus of 586 cleaved HTT.…”

Section: Discussionmentioning

confidence: 99%

“…66,67 The detection of the 586 HTT fragment was performed using a combination of the monoclonal BKP1 antibody raised against the HTT N-terminus and an in-house 586 neo-epitope antibody raised against the C-terminus of 586 cleaved HTT. 47 The level of 586 HTT fragment was normalized to total HTT measures with the combination of BKP1 and 2166 raised against exon 2. BKP1 was labelled with terbium and 2166 and Neo-586 were labelled with D2 (Cisbio Bioassays, Bedford, MA, USA) fluorescent tags.…”

Section: Discussionmentioning

confidence: 99%

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Palmitoylation of caspase-6 by HIP14 regulates its activation

et al. 2016

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Caspase-6 (CASP6) has an important role in axonal degeneration during neuronal apoptosis and in the neurodegenerative diseases Alzheimer and Huntington disease. Decreasing CASP6 activity may help to restore neuronal function in these and other diseases such as stroke and ischemia, where increased CASP6 activity has been implicated. The key to finding approaches to decrease CASP6 activity is a deeper understanding of the mechanisms regulating CASP6 activation. We show that CASP6 is posttranslationally palmitoylated by the palmitoyl acyltransferase HIP14 and that the palmitoylation of CASP6 inhibits its activation. Palmitoylation of CASP6 is decreased both in Hip14 −/− mice, where HIP14 is absent, and in YAC128 mice, a model of Huntington disease, where HIP14 is dysfunctional and where CASP6 activity is increased. Molecular modeling suggests that palmitoylation of CASP6 may inhibit its activation via steric blockage of the substrate-binding groove and inhibition of CASP6 dimerization, both essential for CASP6 function. Our studies identify palmitoylation as a novel CASP6 modification and as a key regulator of CASP6 activity.

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Activated caspase-6 and caspase-6-cleaved fragments of huntingtin specifically colocalize in the nucleus

Cited by 114 publications

References 65 publications

The caspase 6 derived N-terminal fragment of DJ-1 promotes apoptosis via increased ROS production

The caspase 6 derived N-terminal fragment of DJ-1 promotes apoptosis via increased ROS production

Mouse models of Huntington disease: variations on a theme

Palmitoylation of caspase-6 by HIP14 regulates its activation

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